In general, a cartridge or blade unit of a safety razor has at least one blade with a cutting edge, which is moved across the surface of the skin being shaved by means of a handle to which the cartridge is attached. Some shaving razors are provided with a spring-biased cartridge that pivots relative to the handle to follow the contours of the skin during shaving. The cartridge may be mounted detachably on the handle to enable the cartridge to be replaced by a fresh cartridge when the blade sharpness has diminished to an unsatisfactory level, or it may be attached permanently to the handle with the intention that the entire razor be discarded when the blade or blades have become dulled. Razor cartridges usually include a guard, which contacts the skin in front of the blade(s) and a cap for contacting the skin behind the blade(s) during shaving. The cap and guard may aid in establishing the so-called “shaving geometry”, i.e., the parameters which determine the blade orientation and position relative to the skin during shaving, which in turn have a strong influence on the shaving performance and efficacy of the razor. The cap may comprise a water leachable shaving aid to reduce drag and improve comfort. The guard may be generally rigid, for example formed integrally with a frame or platform structure which provides a support for the blades. Guards may also comprise softer elastomeric materials to improve skin stretching.
Wet shaving razors have evolved over the years to include unitary blade members that do not require a blade to be welded to a bent blade support member. Such razor cartridges have begun to be manufactured successfully. However, these razor blades have significant design limitations in order to avoid cracking and breaking of the razor blades during the bending process, such as using thinner blade blanks, larger bend radii and softer steels. Even small scratches and small surface defects in a pre-bending zone can lead to larger cracks or complete failure when the blade is bent in this area. Smaller bend radii put even more stress on the bending zone, thus further increasing the likelihood of failure. Furthermore, cracks in the bending zone also provide initiation sites that facilitate further fracture or even breakage of the razor blade during normal use when mounted in a cartridge housing. Cracks may also facilitate accelerated corrosion that results in failure of the razor blade during use. Failure or fracture of a razor blade can result in an uncomfortable shave to a user. Thus, there is a need for a razor blade manufacturing method that allows for bending of the blade body with minimal cracking or failure of the blade due to surface scratches or imperfections.